The Increase in powerful molecular and genetic tools for Investigation of gene function in the laboratory mouse has greatly increased Interest in this animal as a model for auditory and vestibular research. Although the interpretation of experiments exploiting mice with genetic alterations is not always straightforward, the ability to examine the consequences of modification of a single gene has tremendous implications for molecular investigation of the inner ear. The overall goal of the Mouse Core Is to enable Investigators In the Core Center to carry out experiments with mice, and in particular with genetically modified mice. This ability should enhance present research projects and lead to new experimental approaches, particularly involving collaborations among several Investigators. To provide expertise and services to the Core Center for mouse molecular genetics studies, three specific aims are proposed: 1. To provide mouse husbandry services and training, 2. To provide genotyping services and training, and 3. To provide in utero gene transfer resources. Our service approach is to centralize these activities in a single facility. The model allows individual investigators to focus on their specific research projects while enjoying a more cost-effective model for the use of mice in their NIDCD-funded research programs.